Mixed-pressure turbine.



0. JUNGGREN.

MIXED PRESSURE TURBINE.

APPLIoATloN FILED AUG. 9, 191s,

Patented Jan. 27, 1914.

2 SHEETS-SHEET 1.

Witnesses:

M4- ZZV bij Oscar- Jun Irwvsrwtort ren,

His aqbtorne.

0. JUNGGRBN. MIXED PRESSURE TURBINB. APPLICATION FILED AUG.9, 191s.

1,085,1 38. Patented Jan. 27, 1914 2 SHEETS-SHEET 2.

inventori' Oscar Jun cgren,

His .XTttor-ne.'

UMTED STATES PATENT QFFICE.

GSCR JUNGGREN, 0F SCHENECTADY, NEW YORK, .ASSIGNORATO GENERAL ELECTRIC COMPANY, A CORPORATIGN 0F YORK.

MIXED-PRESSURE TURBINE.

Specification of Letters Patent.

Patented J an. 27, 1914.

Application filed August 9, 1913. Serial No. 783,978.

To all y107mm 'it may concern:

Be it known that I, OSCAR JUNGGREN, a.

citizen oitl t-he United States, residing at Schenectady. county of Schenectady, State of New York, have invented certain new and uset'ul Improvements in Mixed-Pressure Turbines. of which the following is a speciieation,

This invention relates to elastic fluid turbines, and especially to those in which provision is made for operating the machine not only by high pressure steam but also by low pressure steam exhausting from some engine or appliance using high pressure steam. In these so-called mixed pressure units, it is important. that the high pressure part shall be as etcient as an ordinary high pressure turbine. In order to accomplish this and vet not make the machine too expensive, ortooinetlicient by having too many high pressure wheels running idle, when operating under low pressure conditions, it is necessary to utilize as many as possible of the wheels for both high pressure and l'ow pressure operation.

The object of my invention is to provide a mixed pressure turbine which will give a good efficiency for both high and low pres sure operating conditions. The machine comprises one two-row bucket wheel used only for high pressure steam, and a plurality of single-row bucket wheels used wholly for low pressure steam. lVhen the machine is operating low pressure, the high pressure wheel runs idle, but it offers very little resistance as it revolves in the first of the low pressure stages, where the gage pressure is at or below that of the atmosphere. The low pressure steam enters a chamber at one end of the machine, from which it flows to the low pressure wheels through passages outside ot the high pressure wheel chamber. The high pressure steam enters through a number of separately-governed valves and goes through nozzles to the double wheel, which is preferably a little smaller in diameter than the single low pressure wheels. The exhaust from the high pressure wheel goes to a special set ot nozzles arranged inside of and concentric with the first stage low pressure nozzles and delivering said eX- haust steam upon the buckets of the first stage low pressure wheel. A hand-operat ed valve opens communication between the low pressure admission chamber and the chamber in which the high pressure wheel is housed, in order to utilize the aforesaid special nozzles for low pressure operation in case a deficiency in low pressure steam or in vacuum occurs.

In the accompanying drawings, Figure 1 is a side elevation, partly inl section, 0f a turbine embodying my improvements; Fig. 2 is a sectional end elevation; Fig. 3 is a detail section through the hand-operated connecting valve; Fig. 4 is an elevation ofthe thickened portion of the casing containing the passages and ports which supply steam t0 the first stage low pressure wheel; Fig. 5 is an elevation of'a part'of the special nozzles which receive the steam from said passages and ports; Fig. 6 is a cross section of a duplex bucket 'for use on the tirst low pressure stage wheel; and Fig. 7 is a longitudinal section of three such buckets.

The turbine illustrated is a horizontal Ina,-

chine of the Curtis type having a shaft l extending through'a casing 2. On this shaft is the bucket wheel 3 `having two rows of buckets 4 cooperating with the stationary intermediates 5. This is the high pressure wheel and. its stage is separated by the diaphragm 6 from the first of the low pressure stages in which the one-row bucket wheels 7 are located. The high pressure steam is supplied to the machine by the main 8 and its admission to the wheel'3 is regulated by a plurality of nozzle valves 9, each controlling a separate passage 10 leading to a set of nozzles -11 covering a portion of the circumference of the wheel 3. The nozzle valves areoperated in succession by any suitable valve gear, such for instance as levers 12 actuated by cams 13 on a shaft 14. The passages 10 are cored out in a segmental bridge 15, L-shaped in cross section, which is-integral with the inner web 16 and Side wall 17.

i exhaust steam coming from the high pres' is conned to that (ionica ot this patent may be obtained for ranged around the circumference of the web 1.6 and delivering steam to passages 24 leading to the nozzles 25 of the first low pressure stage, arranged just in front of the diaphragm 6. The passages 24 are cored in the outside wall of the casing 2, which is made very thick for this purpose around the high pressure stage chamber.

' The nozzles 25 are' secured to a flange 426 of the casing, and are composed of t-wo portions; an" outer portion having nozzles designed to utilize low pressure steam and an inner concentric portion designed for the sure wheel 3, which reaches said nozzles by Wayof ports 27 cored in the flange 26, near the joint between said flange and the diaphragm 6. The two parts of the nozzles 25 are separated by a continuous partition 28, so that the two currents of steam'cannot in- .termingle; .each part of the nozzle being specially designed to give the best efficiency with the amount and pressure of the particular kind of steam supplied to it. Both parts of the nozzles 25 deliver the steam to buckets on the first low pressure stage wheel 7. These may be ordinary buckets, as shown in Fig. 1, or theymay be specially designed duplex or twofpart buckets, as shown in Figs. 6 and 7. These buckets 29 are provided, at some point opposite the partition 28 in the nozzles, with a lug 30 which extends across the space between two adjacent buckets so as to confine the steam from each part of the nozzle to its own part 'of the bucket. Thse two-part buckets conduce to better eiiieiency when the machine is working with low pressure steam only, because said steam part of the bucket copervating with the low.V pressure part of the nozzle 25.

At lsome point in the web 16 is a port 31 controlled by a hand-operated valve 32; Under ordinary conditions, this valve will remain closed, but in case of a heavy overload, it can be opened to admit the low pressure steam to the high pressure stage chamber and the lower part of the nozzles 25.

Aft/er passing through all the low pressure stages, the steam is drawn ott to the con denser through the conduit 33. The vacuum in the condenser influences all the low pressure stages, so that when -the high pressure wheel 3 is not in use, it runs idle in a body of low pressure steam at not above atmospheric pressure, which greatly reduces the rotation v losses.

`In accordance with the provisions of the p atent statutes, I have described the princlple of operation of my invention, together with the apparatus which I now consider to represent A.the best embodiment thereof;

ve cents each, by addressing the Washington, ZD. C. M

but I desire to have it understood that the apparatus shown is only illustrative, and that the invention can be carried out by other means. l.

What I claim as new and desire to secure by Letters Patent of the United States, is,-

1. A mixed pressure turbine having a casing provided with a hollow head forming a receiving chamber for the low pressure steam, and a segmental bridge extending across said chamber and having high pressure steam passages cored out therein.

2. A mixed pressure turbine having a casing provided' with a hollow head forming a receiving chamber for the lowpressure steam, and a segmental bridge extending across said chamber and having high pressure steam passages cored out therein, the inner web of said head having a plurality of circumferential openings.

3. A mixed pressure turbine having a casing provided at one end with a thick side wall having low pressure steam passages cored therein.

4. A mixed pressure turbine 'having a casing provided at one end with a thick side wall having low pressure steam passages cored therein, and a flange at the inner end of said thickened portion containing ports for exhaust steam from the high pressure A stage.

5. A mixed pressure turbine having a casing' provided with a thickened wall at one end and a flange, passages cored out in said wallen-dV ports in said flange, a nozzle having two parts arranged in line respectively with said passages and ports, and a partition separating said parts.

6. A mixed pressure turbine having a casing provided with a thickened wall at one end and a flange, passages cored out in said wall and ports in said flange, a nozzle having two parts arranged in line respectively with said passages and ports, and a partition separating said parts, each part of said nozzle being designed for a special volume and pressure of exhaust steam.

7. A mixed pressure turbine having passages for low pressure steam and adjacent passages for the exhaust from the high pressure stage, special two-part nozzles delivering said steam, and a bucket wheel having two-part buckets, each part receiving the steam from a corresponding part of said nozzles.

In witness whereof, I have hereunto set my hand this 8th day of August, 1913.

OSCAR ,I UNGGREN.

Witnesses:

BENJAMIN B. HULL, HELEN ORroRD.

Commissioner ot- Patents, 

